Add drag and drop to change column positions

app/Model/Column.php

@@ -0,0 +1,64 @@
+<?php
+
+namespace Kanboard\Model;
+
+/**
+ * Column Model
+ *
+ * @package  model
+ * @author   Frederic Guillot
+ */
+class Column extends Base
+{
+    /**
+     * SQL table name
+     *
+     * @var string
+     */
+    const TABLE = 'columns';
+
+    /**
+     * Get all columns sorted by position for a given project
+     *
+     * @access public
+     * @param  integer  $project_id   Project id
+     * @return array
+     */
+    public function getAll($project_id)
+    {
+        return $this->db->table(self::TABLE)->eq('project_id', $project_id)->asc('position')->findAll();
+    }
+
+    /**
+     * Change column position
+     *
+     * @access public
+     * @param  integer  $project_id
+     * @param  integer  $column_id
+     * @param  integer  $position
+     * @return boolean
+     */
+    public function changePosition($project_id, $column_id, $position)
+    {
+        if ($position < 1 || $position > $this->db->table(self::TABLE)->eq('project_id', $project_id)->count()) {
+            return false;
+        }
+
+        $column_ids = $this->db->table(self::TABLE)->eq('project_id', $project_id)->neq('id', $column_id)->asc('position')->findAllByColumn('id');
+        $offset = 1;
+        $results = array();
+
+        foreach ($column_ids as $current_column_id) {
+            if ($offset == $position) {
+                $offset++;
+            }
+
+            $results[] = $this->db->table(self::TABLE)->eq('id', $current_column_id)->update(array('position' => $offset));
+            $offset++;
+        }
+
+        $results[] = $this->db->table(self::TABLE)->eq('id', $column_id)->update(array('position' => $position));
+
+        return !in_array(false, $results, true);
+    }
+}